1. Field of the Invention
The present invention relates to a space coordinates detecting device provided with a light emitting section having a light source and also provided with a detecting section which senses light emitted from the light source, the space coordinates detecting device being suitable for use in an input apparatus.
2. Description of the Related Art
Heretofore, as an input apparatus wherein information is inputted from the exterior to a screen for the display of various images, there has mainly been used a planar coordinates input apparatus or the like provided with a controller having a joy stick and also provided with switching elements arranged in a matrix form.
The controller having a joy stick is suitable for controlling the movement of characters or operation on the screen in an action game, but not suitable for such an operation as setting a cursor mark to a button which appears in any position on the screen. Besides, since this type of a controller is a cord type, there is a drawback that the controller can be operated only in the vicinity of the screen. On the other hand, the conventional planar coordinates input apparatus requires a wide space for installing a planar indication board in front of the screen; the structure thereof is complicated and its cost is high.
Recently, in view of the above-mentioned drawbacks, there has been proposed such an input apparatus using ultrasonic wave as shown in FIG. 40. In this input apparatus, sound sources 2a and 2b are disposed, for example, on both sides of a screen 1 of the apparatus body and spacedly in the direction of a horizontal axis (X axis). An operating member 3 to be operated manually by an operator is provided with a detecting section for detecting ultrasonic waves generated from the sound sources 2a and 2b . The ultrasonic waves are generated in a pulse-modulated state out of phase with each other. The detecting section of the operating member 3 receives the ultrasonic waves from the sound sources 2a and 2b while distinguishing the waves. Distance La from the sound source 2a and distance Lb from the sound source 2b are calculated, for example, on the basis of a phase difference between the ultrasonic waves received, whereby there are detected coordinates of the operating member 3 on a horizontal plane (Hx-Hz plane).
When the operating member 3 is moved on the horizontal plane (Hx-Hz plane) and an operating button is pushed as necessary, the information received in the operating member 3 is fed by wire or wireless to the apparatus body. In the apparatus body, the position of the operating member 3 on the Hx-Hz plane is calculated and, for example, a cursor mark 4 which has appeared on the screen 1 of the apparatus body is moved.
In the conventional input apparatus shown in FIG. 40, it is possible to detect coordinates of the operating member 3 on the horizontal plane (Hx-Hz plane) and provide the detected information to the apparatus body, but even when the operating member 3 is tilted in the direction of .theta.x or .theta.y while it is stopped in a certain position on the Hx-Hz plane, it is impossible to detect the tilt angle. It is also impossible to detect the angle of rotation of the operating member 3 in the .theta.z direction. Further, although ultrasonic waves can be realized by a simple structure, they are poor in thermal stability and contain much disturbance noise. Thus, many problems still remain to be solved in point of reliability.
As a method not using ultrasonic waves there has been proposed a method which utilizes an alternating current magnetic field to determine position and angle in a three-dimensional space. However, this method requires a large-sized apparatus, which is very expensive.